Ideally, fluid flow about an axisymmetric body will be symmetric. However, in the case of the tangent-ogive cylinder (a generic forebody), this assumption does not hold. At high angles of attack the resulting asymmetry may be enough to overcome the conventional methods of control, causing the body to rotate uncontrollably about the velocity vector. By visualizing the flow about the pitching body, it is hoped that the flow will be better understood, a vital factor leading to the control of said flow.
The data presented were obtained through LDV measurements in the ESM Water Tunnel. The data set consists of three-dimensional velocity in one two- dimensional planes for one hundred times during the motion of the model. Forty-eight planes were used to construct the animation. In addition, the axial vorticity field will be calculated from the velocity field. Contours of the in-plane sectional streamlines and the axial velocity may be displayed simultaneously. In addition, animation will be used to view the entire sequence of the motion.
The picture above depicts the tangent-ogive cylinder in the ESM Water Tunnel with the laser system aligned from the side of the tunnel. The model is mounted so that the pitch axis is vertical.
mzeiger@vtvm1.cc.vt.edu
